This invention relates to a backspace device in a typewriter, i.e. a device for causing a carriage with a printing mechanism to perform a retracting motion by a predetermined pitch.
The conventional backspace device has been of such an arrangement that a wire for drawing a carriage is moved by a cam fixed on a main shaft, a drum provided on a shaft of a wire drum is rotated and the carriage is retracted by a distance commensurate to the value of rotation of the drum. With this conventional arrangement, since a high tensile force acts on the wire, it has been necessary to enlarge the sizes of parts in view of the mechanical strength, and such disadvantages have been presented that the operation is not smooth and the durability is unsatisfactory.
Since the rotation of the wire drum is effected by the main shaft through a link mechanism, there has been presented a disadvantage that a large space was required to house this link mechanism.